The use of animal virus-like particles (VLPs) as vectors for the delivery of genes to mammalian cells has been explored for many years and by a large variety of very different approaches (Schaffer et al., 2008; Lavillette et al., 2001; Soong et al., 2000). Interestingly, however, plant-derived VLPs have not been used for direct gene delivery and expression. In particular, there have been no attempts to use a plant viral capsid to deliver heterologous genes for expression in mammalian cells. High-level expression of mammalian genes in plant hosts, mediated by Agrobacterium plasmids containing the translation-enhancement elements from messenger RNAs of the plant virus CPMV, has been demonstrated for various target proteins and vaccines (Sainsbury and Lomonossoff, 2008). The insect virus baculovector system has also been effectively used for expression of mammalian genes in a wide variety of insect and mammalian hosts (Chen et al., 2011), but such a system cannot be reconstituted in vitro and must be prepared by recombinant plasmid engineering in cell culture.
There is a need in the art for new and/or improved virus-like particles that are useful as vectors for the delivery of genes to mammalian cells.